Cylinder grinding tool



Oct. 30, 1934.. H. w. ZIMMERMAN 1,973,445

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H. w. ZIMMERMAN I CYLINDER GRINDING TOOL Filed Feb. 19, 1930 3Sheets-Sheet 2 j i! z (vz f0)": Herman a! Zimmerman H. w. ZIMMERMA NCYLINDER GRINDING TOOL Filed Feb. 19. 1930 3 Sheets-Sheet 3 Oct. 30,1934.

Patented Oct. 30, 1934 UNITED STATES 1,978,445 CYLINDER GRINDING TOOLHerman W. Zimmerman, Chicago, 111., assignoz' to Automotive MaintenanceMachinery 00.,

Chicago, 111., a corporation of Illinois Application February 19, 1930,SerialNo. 429,618

' 28 Claims. (01. 51-1343) My invention relates to cylinder grindingtools of a character adapted for use either in factory production-workor in the servicing of worn cylinders to bring the surface of thecylinder to true cylindric'ity, accurate diameter and smooth finish.

One of the objects of-my invention is to provide asimple and inexpensivetool of the foregoing character which is capable of fast grinding withhigh efiiciency, which operates without tendency toward seizing, diggingin or increased drag, and which requires less power to operate thantools of this kind which have been used heretofore.

Another object is to provide a cylinder grinding tool which is light inweight and easy to handle, and which is capable of use over long periods01 time with a high degree of accuracy in performance, notwithstandingwear and the usua1 variations commonly experienced in the forming andmachining of tool parts. I

A further object is to provide a cylinder grinding tool havingexpansible and contractible grinding elements which are mounted alongthe radius of the tool but with their median line in radial directionoffset from the tool radius.

Another object is to provide in a cylinder grinding tool of a typehaving a plurality of abrading or grinding elements supported in a bodyor frame for radial expansion and contraction movements, a mounting forthe grinding elements which is such that when these elements are set upnormally in grinding contact with the cylinder wall surface, the maximumworking radius of the tool for that particular setting or adjustment iseil'ective. and, inching or shifting of the grinding element shouldoccur during the grinding: operation, due to abrasive contact with thecylinder wall surface, there will be no tendency toward an increase inthat particular setting thereby avoiding tendency toward increase inabrading-pressure which would tend to cause digging in, seizure orincreased drag.

Still another object is to mount the abrading elements in the tool insuch a way that, if rocking of the same should occur, the tendency willbe to rock the cylinder-wall contacting-surface of the elements towardthe tool center with a consequent relieving of abrading pressure.Specifically, in carrying out this object, I mount the abrading elementswith their median line disposed rearwardly of the tool radius so that,in case of the foregoing rocking of the elements, their median lineswill be rocked toward the tool radius.

A further object is to provide an improved and positive acting means foradjusting the ahrading or grinding elements toward and from the cylinderwall surface without the necessity of removing the tool from thecylinder or detaching the tool or parts thereof from the drivemechanism. Provision is made, however, for ready detachment of the toolfrom the drive when that becomes 0 desirable as in inserting the tool inor removing it from the cylinder.

An additional object of my invention is to provide simple and efficientmeans for avoiding free adjustment play in the adjusting mechanism bytensionally positioning the same in the tool. My invention furtheravoids accidental change in an adjustment once made and serves to insurecontinued cutting or grinding pressure on the abrading means betweenadjustments. This feature of 7 my invention in conjunction with theoffsetting of theabrading carriers, et cetera, insures an exceedinglyrapid grinding of the cylinder. Still another object of my invention isto provide an improved support or clamp means for securing the abradingor grinding stone to its carrier. 7

Other objects are to improve the structure of the tool body or frame; toprovide an improved drive for the tool including means for compensatingfor disalignment between the drive and the tool;v to provide a toolwhich may be readily lengthened as the use requirements make thatdesirable; and to provide a tool wherein a single set of abrasive orgrinding elements will serve for the grinding of a greater number ofcylinders, the wearing of the grinding elements being reduced to aminimum.

Other objects and advantages will become ap parent as this descriptionprogresses and by ref erence to the drawings wherein,--

Figure l is an elevational view of one form of tool embodying myinvention;

Fig. 2is an enlarged vertical section taken substantially on line 2-2 ofFig. l;

Fig. 2a is a plan view of a spring washer for tensioning the movementotthe adjusting dial and adjustment mechanism;

Fig. 3 is a top plan view of the structure as shown in Fig. 2; 1 Fig. 4is a plan view of one of the frame end plates of Fig. 1;

Fig. 5 is a horizontal section taken substantially on line 5-5 of Fig. 2and showing the position of the grinding elements with respect to thetool radius or a line drawn through the exact center of a tool;

Fig. 6 is a separated enlarged 'elevational view of one of the abrasivecarriers and showing my improved abrasive clamping means;

Fig. 7 is a partial section taken substantially on line 77 of Fig. 6; v

Fig. 8 is a section taken substantially on line 8-8 of Fig. 6; I

- ing mechanism embodying my invention.

Referring to the so-called 5-stone type tool shown in Figs. 1 to 5 ofthe drawings, it embodies a frame or body of cage-like constructioncomprising end plates 10 and 11 rigidly secured in parallel spacedrelation by a. plurality of tie-bars 12. In this particular form oftool, the tie-bars are sufficient in number and are positioned toprovide a center space 13 with five radial passages 14 leading outwardlytherefrom, no two of which passages are in diametrically oppositeposition. It will be understood that my invention is not limited to theS-stone type tool, but is equally applicable to tools having any othernumber of stones or radial passages corresponding to passages 14. Forexample, see the tool of Figs. 10 and 11 which will be describedhereinafter.

Abrasive carriers 15 are mounted in the passages 14 in such a mannerthat they are expansible and contractible for varying the workingdiameter of the tool. Specifically, each of these carriers consists of ablade or body portion which is rectangularly-shaped in cross section andwhich has a depth, in radial direction, much greater than titsthickness. A head, greater in thickness than the blade, is formed uponthe outer edge of the blade and is channeled as at 17' to detachablyreceive and support an abrading or grinding stone 18 in a manner whichwill be described more fully hereinafter.

Sole guidance and support for the abrasive carriers 15 is provided bythe end plates 10, 11. To that end, each of the end plates is providedwith guide-grooves or channels 19 which extend substantially from thecenter of the end plate (tool axis) to its outer edge thereby providinga long and deep supporting surface. The blades of each of the carriersare of greater length than the distance between the end plates, thecarrier heads 17 being of lesser length, thereby providing the carrierswith projecting end tongues 20 which are of suitable dimensions to fitsnugly, but slidingly, in the end plate grooves 19. The blades 16 andthe end plate grooves 19 are of suihcient dimensions, in radialdirection and otherwise, to provide a strong and rigid support andguidance for the carriers in all radially adjusted positions.

The abrasive carriers are actuated in their adjustment movement by meanslocated in the tool frame center space 13. Specifically, all of thecarrier blades are of suiiicient depth to enter the center space 13 ofthe cage-frame and their inner edges are suitably shaped for coactionwith adjustable wedging means which is actuable to control the diameterof the tool by simultaneously positioning all of the carriers at similarpositions with respect to the tool axis. This ad- J'usting meansconsists of a center stem 21 rotatably mounted on the axis of the tooland screw threaded at.22 to adjustably receive two wedgemembers or cones23, 24, of identical taper, which cones engage correspondingly slopedwedge-surfaces 25, 26 formed along the inner edges of the carrier blades16. The cones 23, 24 are each provided with a groove 27 through which arod 28 carried by the end plates 10, 11 passes to prevent rotation ofthe cones as the stem 21 is rotated and to insure axial movement of thecones. These cones are arranged in tandem with their small ends upwardso that, upon actuation of the center stem to expand the carriers thecones not only act on the carriers to expand them, but also tend to movethem in axial direction wedging them firmly into the upper end plategrooves thereby aiding in maximum rigidness of the support at thatpoint. The several abrasive carriers are held in the end grooves, andfirmly seated uron the cones, by suitable spring rings 29 which encirclethe ends of the carriers and are seated in recesses 30 in the endsthereof, as clearly shown in Fig. 2. The carriers are freely removablefrom the frame cage by merely removing the spring rings and slippingthem from the end plate grooves.

While the general arrangement of the tool so far described is such thatmaximum rigidity in the support of the slidably-mounted abrasivecarriers is initially provided, the necessary slidefit dimensions of thecarrier blade and its end plate groove may result in a very slightrocking of the carrier when the tool is inserted in the cylinder androtates with the abrasive in contact with the cylinder wall surface, mayexist, or be amplified, due to slight variations in machining thesupporting parts of the tool. It would naturally become more prominentand objectionable as wear due to adjustment, or

otherwise takes place between the carriers and the end plate grooves.

It will be appreciated that, with the inner edge plane surface of thecarrier blades resting on the cones and, ii the radial center line ofthe This condition grooves 19 and carrier blades should coincide withthe radius of the tool, any relative rocking of the carriers upon thecone, such as might take place as above explained, would result inbodily tilting the carriers and consequently increasing the workingradius of the tool. This would obviously cause a tendency toward theabrasive seizing the cylinder wall surface or such an increased dragcondition that the cylinder wall surface might not be accurately groundand there would be a great increase in the power required to rotate thetool.

One of the features of my invention has to do with the prevention ofincreased drag and tendency toward seizure in case there is a tendencyin the operation of the tool toward the above condition. Specifically,the grooves 19 in the end plates 10, 11 are so positioned that thecenter line (in radial direction) of each of them. is located at oneside of, and preferably parallel with, the tool radius or a line passingthrough the exact center of the tool. In other words, the center line ofeach of the end plate grooves is offset radially so that the abradingelements or stones and abrasive carriers are positioned with theirmedian lines (in radial direction) offset from, f

and preferably parallel with, the tool radius. One position of thecarriers and abrading elements or stones 18 with respect to the toolradius is clearly illustrated by the lines a,-a (carrier median line)and b--b (tool radius) of Fig. 5. Another radially ofi'set position ofthe carriers and abrading stones which I have found to efficiently servethe purpose is illustrated in Fig. 11 which will be described more fullyhereinafter.

The tool is preferably, rotated in the direction indicated by the arrowin Fig. 5, and if rocking I of the carrier should occur during rotationof the tool due .to frictional engagement of the abrasive 18 with thecylinder wall surface, the carrier would rock in a direction oppositethe direction of rotation. I, therefore, offset the median line a-a(Figs. 5 and 11) rearwardly (with reference to the direction ofrotation) of the tool radius so that, if such rocking should occur, thetendency will be to rock the cylinderwall contacting surface of theabrasive toward the tool center, rather than away from it, therebyavoiding an increase in the frictional engagement or abrading-pressurebetween the abrasive and the cylinder wall surface and avoiding seizure,increased drag or "digging in. It will be understood that by offsettingthe carrier as explained, its inner edge plane surface is engaged at oneside with the cone surface and that the greater or normal workingdimension of the tool is along a line passing from the center of thetool diagonally through the carrier toward its outer trailing edgeportion. In other words, the maximum tool working radius for theparticular carrier used is provided .as the normal working radius of thetool, and any rocking tendency of the tilt carrier from thatposition ina direction opposite the direction of rotation will tend to adjust thecarrier so that its median line (aa) will move away from and out ofparallelism with the tool radius (b-b), thereby adjusting the abradingsurface to prevent an increase in the working diameter. Each of thecarriers is similarly positioned and, as will be obvious, their medianlines extended inwardly lie similarly tangent to a circle,

- the center of which is common to the center of the tool.

The above matter is presented as a possible explanation of the actionwhich actually takes place during the operation of the cylinder grindingtools illustrated and described herein. It may be possible further toexplain this action in the following way. If a lead pencil having arubber eraser on one end of the same is held with the eraser engaging afiat surface and is inclined in one direction from the perpendicular andmoved in the direction of inclination, it will be noted that frictioncreated by the rubber eraser moving over the surface will create a forcetend ing to move the pencil axially through the hand and in a directiontoward the flat surface. In other words, in dragging the eraser of apencil over a surface, the resistance to the movement of the rubber hasa tendency to pull the pencil out of the actuators hand. If this samepencil is inclined in a direction opposite to the direction of movement,the resistance presented to the rubber eraser moving over the surfacewill have axis of the tool, as the flat surface is to the penoil movedin a direction parallel to said surface. The cylinder wall and eachabrasive element of the illustrated tools, therefore, are comparablewith the above referred to pencil and flat surface. This is true sincefor any given point on the working surface of an abrasive element theradius from the center of the tool frame to that point corresponds tothe perpendicular in the pencil analogy while the line extending axiallyof the abrasive element and its carrier which will intersect the workingsurface at said given point will correspond to the axis of the penciL.The angularity-of the said axial line with respect to its-radius willcorrespond to the inclination of the pencil or the angularity of thepencil with respect to the perpendicular. Applying this comparison to atool, it will be found that for any point on the working surface of anabrasive element positioned in advance of .the tool radius, with respectto the direction of rotation, the axial line for that point will beinclined from its' radius toward the direction of rotation and thatradius, the axial line for that point will be in-- clined from itsradius in a direction opposite to the direction of rotation. Theportions 'of the working surface in advance of the said tool radius,therefore, have a tendency to move radially outwardly toward thecylinder wall. The portions of the working surface of the tool locatedrearwardly of said tool radius therefore have a tendency to move awayfrom the cylinder wall.

It will be noted that the abrasive elements of the tool shown in Fig. 5have a major portion of their working surfaces located rearwardly of thetool radius line 12-12 and therefore there will be a major portion ofthe working surface ofeach abrasive element operating to force eachelement and its carrier radially inwardly against the rigid surfaces ofthe adjusting cones. It is believed, therefore, that there will be aresultant force or component which will succeed in holding the abrasiveelement and its carrier inwardly against the adjusting cones. With thearrangement shown in Fig. 11, with the entire workingsurface of eachabrasive element located rearwardly, with respect to the direction ofrotation, of the tool radius line 12-12, the entire surface of theabrasive element will be working to force the element and its carrierinwardly toward the axis of the tool.

With this explanation in mind, it will be apparent that when an abrasiveeiement rocks, due to wear or the like, this reciting motion will be ina direction opposite to the direction of retation of the tool and willtherefore cause an additional portion of the working surface of eachabrasive element to be moved rearwardly, with respect to the directionof rotation, of the tool .radius line b-b. Any wear or imperfectiondeveloped during manufacture which results in a way that they may bereadily and quickly detached; and it is also quite essential that theybe desirable features. Specifically, the abrasive or grinding stone 18is mounted, preferably, in a metal channel-shaped holder 31 and thisholder with its stone is mounted in the channel 1'7 of the carrier head.The carrier head, at one side is provided with, preferably, two cut-outs32 which extend through that side of the head to the channel 17. Thesecut-outs are each adapted to receive a clamp block 33 which is securedand mounted as follows: The stone carrier just inwardly of its head andadjacent the cut-outs 32 is provided with a boss or clamp-seat surface34 which is raised above the base of the cut-outs, and upon which theinward edge of the clamp block is adapted to rest and rock. The centralportion of the clamp block and the carrier head are provided withaligned openings, the latter being threaded, to receive a screw 35 fordrawing the clamp block tightly in place. As will be obvious from Fig.8, with the inward edge of the clamp block resting on its seat 34 andits outer edges resting against the stone support 31, the clamp block ismoved laterally and inwardly, rocking about its seat 34 when the screw35 is tightened, forcing the stone support 31 toward its seat in thehead channel 1'7 where it is firmly held. The screw 35 is of sufficientlength to extend a substantial distance through the carrier head so thatthe likelihood of the screw working loose is reduced to a minimum. Withthis arrangement, a relatively large diameter screw may be used whichfurther tends to reduce the possibility of the screwworking loose. Thehead of the screw is also countersunk in the clamp block so that anincreased friction-holding surface is provided which further tends toguard against loosening of theclamp means. The use of the large screwsenables them to be more readily handled and tends to provide forreadiness and ease in the replacement of the stones.

For rapid work, either in factory productionwork or in the servicing ofworn cylindersfit is highly desirable that adjustment of the abrasive orgrinding stones be accomplished without necessity of removing the toolfrom the cylinder and without the necessity of making numerousmeasurements in order to determine when the proper diameter of thecylinder has been reached. To that end. my invention provides anadjusting mechanism which is accessible, and remote from the cylinder,and which provides for readiness and positiveness in the adjustment ofthe stone carriers so that the work of the operator is greatlyfacilitated. Specifically, with reference to Figs. 1 to 5, the upper ortop end plate 10 is provided with a cylindrical extension 36 disposedalong the axis of the tool. This extension has an axial opening 37through which the center stem 21 passes and finds guidance and bearingsupport. An extension sleeve-38, which may be of any desired length tomeet the requirements of each particular tool and its use, isscrewthreaded upon the extension 36. The upper or outer end of theextension sleeve 38 screw-threadedly receives and rigidly supports adial cage 39 which rotatably supports a cylindrical adjusting dial 40with its peripheral edge exposed (Fig. 1). The center stem 21 is ofsufiicient length to extend upwardly through the extension sleeve 38,.

through a center opening 39' in the .dial-cage39 and through theadjusting dial to which it is fixed by a pin 41. The upper end of thisstem, preferably, finds a bearing support in the upper part of the cage39 so that the adjusting stem is firmly and positively positioned forrotational movement.

Obviously, rotational movement of the dial 40 relative to the dial cagerotates the center stem -21 moving the cones 23, 24 and the carriers ina direction dependent upon the direction of rotation of the dial. Theupper part of the dial cage is provided with a horizontal projection 42serving as a pointer or indicator which cooperates with the dial marks43 to inform the operator as to the extent of any particular (or thetotal) adjustment of the grinding stones and the substantially correctextent to which the cylinder wall surface has been ground. In the use ofthe dial marks 43 (which may represent thousandths). when the tool isfirst inserted in the cylinder and the stones are set up until theyengage the cylinder wall surface. the projection or indicator 42 mayregister with one of the dial marks. If the operator wishes to removesay five-thousandths from the cylinder wall surface, the dial may beadjusted from time to time until its initiallyregistering mark 43hasmoved around five points with respect to the indicator 42. The cylinderwill have then been ground to the five-thousandth extent, less theamount of the stone wear. The grinding (and adjustments) may becontinued to a desired extent to compensate for stone wear.

Since the dial 40 serves to support as well as actuate the center stem21, there is the probability, unless guarded against, of the dialaccidentally being rotated, due to vibration, etc,, of the tool (or itsparts) during operation which would result in considerable inconvenienceto operator and inaccurate grinding of the cylinder. My inventionprovides against such a condition by placing the dial under a constanttension so as to frictionally re'slst rotation of the dial.Specifically, the overall width of the dial is slightly less than thedepth of the cage opening 39 in which it is positioned; and its hub 40*is of less width than its outer rim 40 providing a space between thedial hub and bottom of the cage opening 39 in which is received acylindrically-shaped, dished, spring washer 60. This washer is of suchsize and shape that with the parts assembled as shown in Fig. 2, it isunder a slight tension; and it is capable of slight compression so thatwhen the tool is set up in the cylinder the spring washer may be placedunder additional tension. Thusly, a constant tension is exerted on thedial to frictionally resist rotation of it and the center stern, therebyinsuring that an adjustment once made will be maintained accurately toproperly inform the operator. This arrangement takes all adjustment playout of the adjusting mechanism. The dial, stem and cones are tensionallypositioned as a unit, thereby tending to hold the grinding stones inabrading contact with the cylinder wall surface under a continuedgrinding pressure throughout any particular adjustment setting,resulting in a more rapid grinding operation.

li"he tool may be driven by any desired power means which may or may nothave a fixed mounting; but in either case it is desirable to provideconnecting means between the tool frame and the drive which compensatesfor disalignrnent of these parts, which insures an accurate and freegrinding action and which is readily separable to permit ready handlingof the tool and its drive in inserting the tool in and removing it fromthe cylinder. In the form of Figs. 1 to 9,

inclusive, I provide that as follows: The upper part of thedial cage 39has an opening 44 in which a short stem 45 is fixed by a pin 46. Aparti-spherical head 47 is fixed on the outer end of the stem 45 by apin 48, the projecting ends of which project outwardly for bayonet-lockengagement in L-shaped slots 49 in a drive socket 50 (Figs. 1 and 2).The upper wall of this socket has an opening which screw-threadedlyreceives a flat-sided drive shank 51 held in place by a lock-nut 52. Itmay be desirable to use different shaped drive shanks of differentlengths and the detachability of the shank 51 readily provides for that.

The drive shank 51 is adapted to be connected directly to the powermeans, and its rotation results in rotation of the tool. The arrangementof the drive connection shown in Figs. 1 and 2 is well suited for usewith power means which is not fixedly supported as may be the case attimes in using the tool for servicing operations and where it issupported by hand. In the use of fixedly-supported power means wheredisalignment in all directions need be taken care of, as may be the casein factory production-work, I may employ the drive spindle shown in Fig.9. This spindle comprises a stem 53 having on its lower end a socket 54(mounted similarly to the socket 50) with L-shaped slots 55 providing abayonetlock connection, and having on its upper end a parti-sphericalhead 56 secured by a pin 57, the ends of which pin project from the headfor bayonet-lock connection. This spindle is adapted to be insertedbetween the drive shank 51 and the dial-cage 39 with its socket 54bayonet-locked to the head 47 and its head 56 bayonet-locked with thedrive socket 50. With this connection, slight disalignment between thetool frame and the drive will not hinder free grinding movement of thetool. Further, this intermediate spindle may be used to lengthen thetool as a whole, and

different length spindles may be used as desired.

This arrangement further provides for the use of a more rigid tool' bodyand adjusting mechanism, and provides for adjustment of the tool from apoint remote from the cylinder without the use of joints, or likeconnections, in the adjusting mechanism or its supporting parts.

In Figs. 10, 11, 12 and 13, I have shown another form of my invention asapplied to a socalled 4-stone type of cylinder grinding tool which willnow be described. The tool frame or body is constructed similarly tothat shown in Figs; 1 and 2, except that four, instead of five, tie bars'70 are employed to rigidly join the end plates 71 and 72 together inspaced relation. These tie bars divide the frame into a center space 73with four radial passages 74 leading therefrom. The end plates are eachprovided with four grooves 75 (Fig. 11), each of which is offsetradially with its median line disposed'rearwardly (with respect todirection of rotation) of the tool radius. These grooves support andguide the slidably adjustable carrierslfi, each of which comprises abody shaped and mounted similarly to the body of thepreviously-described carrier. The outer edge of the carrier body isprovided with an enlarged, preferably integral, head 106 having achannel 107 in which is carried the grinding stone 108 and its channelsupport 109. The channel 107 is similar to that of thepreviously-described form, except that its median line tool radius (Fig.11note lines a--a and bb) riers, under the foregoing conditions, willnot re- (see line c-c, Fig. 11) is oflset with respect to the medianline (a-a, Fig. 11) of the carrier body. The median line of the carrierbody 105 in the tool is so positioned with respect to the 80 that withthe stone-receiving channel'of the head 106 offset as described theradius of the tool passes adjacent the forward edge of the carrier body(compensating for the thickness of the stone channel support 109) andsubstantially coincides with the leading edge of the abrading stone 108.With this arrangement, the slightest rocking movement of the carrierwill not result in increased abrading pressure. This form of carrier andits manner of positioning is well adapted to all of the previouslydescribed forms.

The clamp means for holding the grinding stone 108 and its support 109in place is similar to that shown in Fig. 8. Briefly, the channel head106 is provided at one side (preferably, the side located nearest thecarrier body) with cutouts 110 adapted to receive clamp blocks 111. Thebase 112 (Fig. 13) of each cut-out is countercut so that its plane islower than that of the adjacent carrier body surface. The butt or inwardend of the clamp block 111 rests on the carrier body surface adjacentthe cut-out and when the screw 113 is tightened in place, theunsupported end of the clamp block is rocked toward the stone support109 forcing the same 105 into its channel-seated position where it isfirm-1y held.

It is quite customary in cylinder grinding tools of the 4-stone type toutilize two opposite carriers to support abrasive or grinding stones108, the 1 0 I other two opposed carriers serving as guides, so tospeak, for properly positioning the tool with respect to the cylinderwall surface so that the desired cylindrical finish will beaccomplished. Heretofore, the cylinder contacting part of these 15 guidecarriers has taken the form of removable guide elements supported by thecarriers in engagement with the cylinder wall surface, which elements,in some instances, take the. general shape of the grinding stone and areformed of 0 wood, oil-impregnated cotton belting, fibre and othersimilar materialsf These prior-used materials are objectionable for thereason, among others, that they do not wear away proportionately to thewear in the abrasive. It has usually been found that the abrasive wearsaway more quickly with the result that, in the grinding operation, afterthe abrasive has worn in a single grinding operation, the guides nothaving worn proportionately are the only part of the tool 3 contactingwith the cylinder wall surface as the tool rotates. In tools of acharacter wherein all of the carriers are simultaneously adjusted tosimilar extents, further adjustment of the carsult in adjustment of thegrinding stones into proper grinding contact with the cylinder wallsurface. It becomes necessary, under these circumstances, to remove thistool from the cylinder and dress the guide surfaces before the tool will4 operate properly. Naturally, such conditions of operation make theseprior tools expensive to operate and materially increase the cost to thecar owner of the grinding of the cylinders.

I have found that the foregoing objectionable conditions can be overcomeby using for guide contact a relatively hard felt material which ispreferably (but not necessarily) impregnated with a varnish material ofthecharacter used ordinarily in connection withelectrical constructionwork. This varnish material readily penetrates the felt material andhardens sufilciently to provide a guide element, such as 78, supportedby the guide carriers of Fig. 11. A guide element of this character hasa sufliciently stiff body to stand up under guide-pressure conditionswhile, at the same time, having the ability to wear in substantially thesame proportion as the cylinder grinding stones. In some instances, Imay use a high grade medium-hard felt material untreated, or I may treatonly the sides of such material with cement, varnish, lacquer or somesimilar material to stiffen its side walls sufliciently to support itagainst free resiliency when in contact with the cylinder wall surface,without interfering with its ability to wear away at the same rate asthe grinding stone or other abrasive. With such an arrangement, thegrinding may be carried on, in the grinding of a single cylinder,continuously and rapidly without removing the tool from the cylinder todress the guides.

As shown in Fig. 10, the adjusting mechanism for expanding andcontracting the carriers 76 is similar to that of the form firstdescribed, except that the structure for supporting and actuating thecenter adjusting stem 79 is somewhat different. Specifically, (Fig. 10)the end plate '11 has an outward sleeve extension 86) upon which thereis secured by screw pins 81 the cylindrical portion 82 of a cage-likedrive member 83. 'This drive member is provided with an integralpartispherical head as carrying a pin 85 which is adapted to be engagedby a socket part of the drive corresponding with the socket 50, shown inFig. 2, to provide for universal adjusting aligning movements betweenthe drive and the tool.

The center stem 79 extends outwardly through and finds bearing in theend plate ll and has its outer end secured centrally to an adjustingdial 86 by a pin 87 or other suitable means. As will be noted in Fig.12, the drive member 83, above its cylindrical bottom part 82 is open,its upper and lower parts being joined by opposed arm sections 88,thereby exposing the peripheral knurled surface of the adjusting dial8'3 so that the same may be readily grasped to rotate the center stem 79and move the cones 89 to expand. and contract the carriers '76 as wilibe understood from the description given hereinabove.

In this particular term of my invention, the adjusting mechanism istensionaliypositioned in the tool ior maintaining adjustments and forcontinued grinding pressure during any one adjustment, as follows: Theouter surface or the end plate '11, which is the bottom of the extension80, is provided with a reduced bore in which there is seated a springwasher 90 similar to the spring washer 60 shown in Fig. 2a. A sleeve 91is mounted upon the outer end of the stem 79 between the under face ofthe dial 236 and the washer 90, this sleeve being of sufiicient lengthto place the washer 90 under slight compression in the normal assembledposition of the tool. This structure operates similarly to thetensioning structure shown in Figs. 2 and 2a.

In Fig. 14, I have shown a modified form of drive connection between theadjusting dial 86 and the center stem 79*. More particularly, the dial86 has centrally secured therein as by pin 92 a short stem or shaft 92,one end of which is seated for guidance and support in a central bore inthe upper portion of the cage-like drive member 83. The other end ofthis stem 92 extends beneath the dial 86 and supports a pin 93, the endsof which project slightly beyond the outer surface of the stem. Theadjusting stem extends outwardly through the end plate '71 and has anenlarged head 94 having a central bore for receiving the lower end ofthe stem 92. The opposite side walls of the head are slotted into itsbore to receive the projecting ends of the pin 93 to provide a readilyseparable but positive drive connection as between the stem 92 and theadjusting stem '79. A spring washer 95 similar to that shown in Fig. 2ais disposed beneath the stem head 94 and the outer surface of the endplate 71 to provide for tensioning of the adjusting mechanism as in theform first shown and described.

With this structure, the tool parts may be readily disassembled bymerely removing the screw pins 96 which lock the drive member 83 uponthe end plate 71. Other than the above, the operation of this tool isthe same as that shown in Fig. 2.

The tool drive structure shown in Fig. 15 is quite similar to that shownin previous figures, except that the end plate 97 of the tool and thecage-like drive member 98 and the parti-spherical universal connectionhead 99 are all formed as one integral piece. In this form, theadjusting mechanism tensioning means which takes the form of a springwasher 100 is confined between the bottom of the cage opening 101 andthe under-side of the dial 102. The under-side of the dial is providedwith a shallow bore 103 to readily accommodate the washer 100.

It will be understood that while I have shown and described severalembodiments of my invention, other changes in details and arrange mentof parts may be made without departing from my invention as defined bythe claims which follow.

I claim:

1. In a tool of the character described, a cageframe having end plateswith radial passages therebetween, a plurality of long, deep groovesextending in radial direction in said end plates, corresponding groovesin opposite end plates being vertically aligned, and all said. groovesbeing so positioned that their median line in radial direction is offsetfrom the tool radius, and abrasive carriers mounted in said radialpassages and having their ends slidably seated. in said oriset grooves.

2. In a tool of the character described, a cageframe having end plateswith radial passages therebetween, a plurality of long, deep groovesextending in radial direction in said end plates,

corresponding grooves in opposite end plates b..-

said radial passages and having their ends slidably seated in saidoffset grooves.

,3. In a tool of the character described, a rotatable cage-frame havingend plates with radial passages therebetween, a plurality of long, deepgrooves extending in radial direction in said end plates, correspondinggrooves in opposite end plates being vertically aligned, abrasivecarriers mounted in said radial passages and having their ends slidablyseated in said grooves, and all said grooves being so positioned thatthe median line of said carriers in radial direction is offsetrearwardly, with respect to direction of rotation, from the tool radius.

4. In a tool of the character described, a cageframe having end plateswith radially directed grooves, means dividing said frame into apinrality of radial passages between said end plates, abrasive carriersmounted in said passages and having body parts with end portionsslidably supported in said grooves, said' carrier bodies having planeinner edge surfaces, cone-shaped adjusting devices engaged with theplane inner edge surfaces of said carriers, means for adjusting saidcone devices, said grooves being so positioned that the carrier planeedge surface engages said cone surfaces at one side of the median line,in radial direction, of said carrier 5. In a tool of the characterdescribed, a cageframe, means forming a plurality of radial passages insaid frame, abrasive carriers mounted for expansion and contractionmovements in said passages, said carriers having inner edge planesurfaces extending into the central portion of said frame, adjustingdevices mounted in the central portion of said frame having surfacesupon which said carrier plane surfaces seat, means for adjusting saiddevices to expand and contract said carriers, and means for sopositioning said carriers in said passages that their inner edge planesurfaces are seated upon said adjusting device surfaces to one side ofthe radially-directed median line of said carriers. 6. In a tool of thecharacter described, a frame,

abrasive carriers mounted in said frame for toolexpansion andtool-contraction movements, said carriers being of sufficient dimensionin radial direction to extend into the central portion of said frame andhaving inner edge plane surfaces, adjusting means mounted in the centralportion of said frame and including elements having surfacesupon whichthe plane inner edge surfaces of said carriers seat, the mountmg forsaid carriers being so positioned with respect to the tool radius thatthe median line in radial directionof each carrier is offset from a linepassing through the exact center of the tool.

7. In a tool of the character described, a cageframe having end platesspaced in such a manner as to provide in the frame a center space andradial passages leading therefrom, said endplates having correspondingradially-directed grooves the median lines of which in radial directionare offset from the tool radius, abrasive carriers mounted in saidradial passages and each having a bladed body part the ends of whichslidably seat in said groov'es, cone-shaped ad usting devices mounted insaid frame center space, said carrier bodies being of suchlength as toextendinto the frame center space and being so shaped that plane inner,edge surfaces seat upon said cone devices, the radial offsetting of saidend plate grooves positioning said carriers so that they seat upon saidcones to one side of the center of their plane surfaces.

8. In a cylinder grinding tool a frame, an abrading element, a carrierfor said element mounted to extend in' radial direction in said frame,the

. inneredge of said carrier being fiat, an adjusting member having acylindrical surface engaged by the inner edge of said carrier, saidcarrier so engaging said member that upon bodily rocking motion of thecarrier in a direction opposite to the direction of rotation of thetool, the surface of said element in contact with the cylinder wallsurface is rocked closer to the tool center thereby reducing the workingradius of said carrier relieving the abrading-pressure-contact betweenthe abrading element and the cylinder wall surface preventing seizureand increased drag.

9. In a tool of the character described, a stone carrier having arectangularly-shaped stone-receiving channel therein for receiving arectangularly-shaped stone-unit, and means for securing said stone unitin said channel comprising a flatface detachable clamp block mounted inone of the channel sides with one end engaging one of the flat sides ofthe channel mounted stone unit, a seat on said carrier having a seatingsurface lying in a plane substantially parallel with said flat side ofsaid stone unit and on which the other end of the flat face of saidblock rests, and a fastening device adjustably engaging said block andcarrier to secure the stone in place.

10. In a tool of the character described, an abrasive carrier having achanneled head, an abrading element mounted in the channel of said head,one of the sides of said head channel having a cut-out, a clamp blockhaving a plane surface mounted in said cut-out with one end engagingsaid element, the base of said cut-out being counter-cut so that it islower than the carrier surface located adjacent and inward of said head,said block being of such length that its other and rests and rocks uponsaid carrier surface last-mentioned and fastening means engaging saidblock and said carrier which rocks the block about its said other endsupport when it is tightened pressing laterally and inwardly upon saidelement.

11. In a tool of the character described, a body, abrading meanssupported in said body, means, including a rotatable stem memberextending through said body to be journalled therein and anexteriorly-accessible stem-rotating element, for adjusting said abradingmeans, and tensioning means acting directly on said stem-rotatingelement for fricti'onally resisting rotation of'said stem member.

12. In a cylinder grinding tool, a body, abrading elements supported insaid body, independent adjusting devices in said body acting on saidele- 13. In a tool of the character described, a frame.

abrasive carriers mounted in said frame for expansion and contractionmovements, means for successively adjusting said carriers withoutremoving the tool from the cylinder including a rotatable frame and anexposed rotatable actuator connected to said stem member remote fromsaid frame, and spring means yieldably opposing axial movement of saidstem member for tensionally positioning the adjustingmeans in saidframe.

14. In a tool of the character described, a rostem member extendingthrough said V tatable cage frame having end plates with alignedgrooves, an abrasive carrier extending radially within said frame withits opposite ends slidably mounted in said grooves, an abrading elementsupported by said carrier, means for expanding and contracting saidcarrier, said carrier-supporting grooves each having their median linein radial 15. In a tool of the character described, a rotatable frame,an abrasive carrier extending radially within said frame, an abradingelement supported by said carrier, and means supporting said carrierwith its median line in radial direction offset rearwardly, with respectto direction of rotation, from the tool radius passing substantiallyparallel therethrough, said carrier supporting said abrading elementwith the median line of the latter in radial direction oflsetrearwardly, with respect to direction of rotation, from. the said medianline of said carrier.

16. In a tool of the character described, a rotatable frame havingspaced end plates with the grooves extending radially inwardly, acarrier member adjustably supported in said grooves, an abrading elementsupported by said carrier, .said grooves being so positioned relative tothe radius of the tool and said element being so positioned relative toits carrier that the leading edge of said element coincidessubstantially with the tool radius.

17. In a tool of the character described, a rotatable frame, a carriermember adjustably supported by said frame, a channeled head along oneedge of said carrier, the median line of said head channel in radialdirection being offset with respect to the median line in radialdirection of the carrier, an abrading element mounted in said channel,said carrier being so positioned and said channel being so offset thatthe tool radius passes through said element adjacent its leading edgewith respect to direction of rotation.

18. In a tool of the character described, a frame having end plates withcorresponding radially directed grooves therein, all said grooves beingso positioned that the median line of each in radial direction is offsetfrom the tool radius, carriers siidably supported at their ends in saidgrooves, each said carrier having a. channeled head along its outeredge, the median line of each said head channel in radial directionbeing ofiset from the median line of the respective carrier, and anabrading element supported in the channel of each said carrier head.

19. In a tool of the character described, a frame having end plates withcorresponding radially directed grooves therein, all said grooves beingso positioned that the median line of each in radial direction is offsetrearwardly from the tool radius, carriers slidably supported at theirends in said grooves, each said carrier having a channeled head. alongits outer edge, the median line of each said head channel in radialdirection being oifset rearwardly from the median line of the respectivecarrier, and an abrading element supported in the channel of each saidcarrier head, the arrangement being such that the tool radius passes approximately through the leading edge of the abi'ading element.

20. In a tool of the character described, a frame having end platessupported in spaced relation to provide a central space with radialpassages leading therefrom, a center stem journalled in said end plates,abrasive carriers mounted in said radial passages, adjusting devicesadjustably supported by said stem and engaging said carriers forexpension and contraction movements, a hollow extension projectingrigidly from one of said end plates, an exteriorly-accessible adjustingmember mounted on and rotatable relatively to said extentherein;

sion and connected to said stem for axial support of the latter, and auniversal drive connection associated with said extension outwardlybeyond said adjusting member.

21. In a tool of the class described, a frame having spaced end plateswith aligned grooves abrasive carriers supported in said grooves forexpansion and contraction movements; means for expanding and contractingsaid carriers including a stem member mounted on the axis of the tool,said frame having a rigid hollow drive extension on one of said endplates through which one end of said stem is projected; an adjustingmember supported by and rotatable relatively to said extensiomsaidadjusting member being connected to said stem for support of the latternormally for rotation, and a universal drive connection on saidextension outwardly beyond said adjusting member.

22. In a cylinder grinding tool, a cage-like frame having end platessupported in spaced relation, the adjacent faces of said end plateshaving aligned grooves extending from their periphery to their centralportion, abrasive carriers guidingly supported in said grooves, abrasivemembers supported by said carriers and having their median lines offsetfrom the tool radius, and means for expanding and contracting saidcarriers.

23. In a cylinder grinding tool, a cage frame having end plates, aplurality of grooves in said plates extending from their periphery totheir central portion, corresponding grooves in opposite plates beingaligned and each said groove having its median line oflset from a toolradius line passing therethrough substantially parallel with its medianline, abrasive carriers having end portions slidably mounted in saidgrooves, and means for sliding said carriers back and forth in saidgrooves to expand and contract the tool.

24. In a tool of the character described a cage frame having end plateswith radially directed grooves, means forming a plurality of radialpassages between said end plates, abrasive carriers mounted in saidpassages with end portions supported in said grooves, adjusting devicesengaged with the inner, longitudinal edges of said carriers, means foradjusting said devices to expand said carriers, said grooves being sopositioned that the median line oi the inner longitudinal edges of saidcarriers is to one side of the point of engagement between said car--rier edges and adjusting devices.

25 In a cylinder grinding tool, a cage-frame having spaced end plates,grooves in the inner faces of said plates, abrasive carriers having endportions slidably mounted in said grooves for support thereof, abrasiveelements supported by certain of said carriers, and means for expandingand contracting said-carriers, said end plate grooves being so locatedthat their median lines a and those of said carriers are offset from thetool radius.

26. An abrasive carrier for tool of the character described whichcomprises a body portion,

a channelled head supported bysaid body portion, an abrasive unitconsisting of an abrasive member and a channel-shaped support thereformounted in the channel of said head, one of said head channel sidesbeing interrupted to provide openings therethrough, raised seat elementson said carrier aligned with said openings and located inwardly of thebase of the channel of said head, a clamp block mounted in said outoutwith its inward-end resting on said seat, and means engaging said blockand carrier for seamaze curing said block in place and for rocking itsouter end inwardly against said abrasive member.

27. In a tooi of the character described, a retatable frame, an abradingelement having a working face portion engageable with the cylinder wallsurface, and means including a carrier member for supporting saidabrading element in said frame so that the entire width of said workingface will be positioned rearwardly, with respect-to the direction ofrotation, of a tool radius passing through said carrier member inparallelism with the central radial plane of said carrier member.

28. In a tool of the class described, a rotatable frame havingradially-directed passageways and opposed end members withradially-directed grooves therein, carrier members, having wallcontacting elements, mounted in said passageways with end portionsthereof mounted in said grooves for expansion and contraction movements,all of said grooves being so positioned that their-median lines inradial direction are offset from the axis of the tool, means locatedbetween said and members in engagement with said carrier members andadjustable in-one direction axially of the tool for expanding saidcarrier members and for limiting contraction movement of carrier membersto variable extents, means operable upon adjustment of said first meansin an opposed direction for contracting said carrier members, and meansforadjusting said first means in both said directions.

HERMAN W.

